Practically off the grid!

 I have made a number of energy saving changes to my home in recent years and one of the changes I have been most happy with is the radiant heating system.   It was easy to install, has operated efficiently,  and creates a very comfortable living space.

A radiant heating systems work by heating a large mass within a home and allowing that mass to radiate its heat throughout the building.  Most commonly the mass chosen is the floor of the house but I have also seen radiant walls and ceilings.  The old style cast iron radiators are a form of radiant heat but they are a bit more intrusive because of their placement right in the living spaces and their higher operating temperatures.  When the entire floor surface is used to radiate heat, that surface does not need to be as hot as the old style radiators and the heat distribution system is tucked away neatly inside the floor.

The installation of the radiant heating system was simple.  I have a fairly small house of only 440 square feet so I appreciated that the job was greatly simplified compared to what it would have been in a much larger home.  I chose to install the radiant heating pipes underneath my main floor between all of the floor joists.  This was mostly because my house was already built.  Had it been a system for a new house I might have opted to install the piping above the subfloor but in my case an underfloor application was the simplest and had been shown to be effective so that was my choice.  My research told me that I should keep my loops around 200-400 feet in length so as not to overpower the pumps and still have even heat distribution.  To meet this requirement I decided to use two radiant heating loops about 300 feet long.  One loop included both bedrooms and the bathroom and the other loop included the living area and kitchen.  There are AC pumps available that could drive both loops of this system but I chose to use one smaller DC pump for each loop.  The DC pumps I bought from WSE Technologies are simpler and more efficient than AC pumps and having one pump for each loop also makes it easy to add a second thermostat to the system later on if I want to have different temperature settings for each heating zone.  As for now, I have one programmable thermostat powering both 12V DC pumps.  The pumps are on an independent circuit hooked up to a 12V battery and charger temporarily until I invest in more PV panels to power the whole system.  So those are the radiant system essentials: hot water source, heating loops, manifold, pumps, and thermostat. 

Once I had the delivery of the heat sorted out I needed to make sure that heat is transfered efficiently from the pipes to the floor.  Air is not a great conductor so first I fastened right against the bottom of the floor.  In addition to this, I stapled aluminum heat transfer plates over the piping to increase heat conduction bewteen the pipes and the floor.  The plates will extract more heat from your pipes and save you energy because you will not need to circulate as much water.  Your pumps will also last longer because they will not run as often.   I also stapled reflective bubble foil between the floor joists to reflect radiated heat back up to the floor.  I started using the system without the foil at first and found that the basement became uncomfortably hot.  The addition of the foil between the joists made a huge difference.  My basement now stays at a comfortable temperature but is still often a degree or two warmer than the main floor in the heating season.

This is my second winter with this radiant heating system installed and I have observed some significant improvements in the energy efficiency over my older forced air heating system.  The most noticeable improvement was actually the drop in my electrical bill because the DC pumps draw much less power than the fan in the old furnace.  I have also observed a large drop in my gas bill.  Radiant heating has a reputation of being more efficient than forced air systems but I can’t attribute the decrease of my gas bill to the radiant system alone.  The switch to radiant heat meant using a gas boiler (also a bit old) for the grid tied heat source which is probably a bit more efficient than the old furnace.  The radiant heating system also allows the contribution of heat from my solar water heating system.  What I can say is that all of these factors combined have slashed my heating bill by half and that is pretty significant!  

As if the energy savings were not enough of a reason to celebrate, the new radiant heating system has also made my living spaces more comfortable.  Because the floor is always warm, I now have the pleasure of walking around with warm and even bare feet in the middle of winter.  I used to be awoken in the night from the abrupt start of the old furnace fan but the new pumps quietly deliver the heat without any disturbance.  I also have enjoyed the absence of my furnace in my basement.  It was a monster of a thing that took up a lot of space and I now get to decide what else I could do with that space.  The spider like furnace ducting is also gone and that cleared up even more space in the basement.  Oh yeah and my old chimney is also gone because my water heater can be vented out a side wall.  So not only have I experienced an increase in comfort I now have significantly more space and in my small home that amount of space makes a noticeable difference.

To summarize my experience with radiant heating, I have been impressed with the ease of installation, the simplicity and efficiency of the working system and the improved comfort in my home.  I recommend radiant heating to everyone who asks me about it.